You're no worse off than people who just plain visit facebook pages without realizing that a lot of people use the "who just visited my profile?" app with facebook.
There was a discussion here from people arguing about whether someone can see that people simply visited their page. People were arguing yes, no, and I never did see anyone actually get or give the factual information they were seeking: by DEFAULT no you can't see who clicked to view your profile. HOWEVER one of the most popular facebook app add-ons (aside from games like Candy Crush, and the add-on that lets you see everyone who un-friends/un-follows you on a daily basis) is the add-on that allows you to get notifications every time someone views your profile.
You will never know if someone has that add-on installed or not. I personally always assume that EVERYONE has it installed, that way I will never end up off-guard. JMO. I never click facebook pages without either logging out of facebook completely, or assuming the person at the other end may see a link to my own profile in a notification that I just viewed their page.
There are multiple versions and iterations of this app. Here's a generic facebook search for it that shows some results in case anyone is doubting that this is a "thing".
https://www.facebook.com/search/top/?q=who's viewed my profile
Edited to add: yes the people who say just set your page to private and block him are spot-on. Great advice! So I will just add a brief moment of humor (hopefully) here - I advise that whatever you do, you DON'T change your facebook name in an attempt to keep him from seeing it, because my son's friend for some reason thought it would be hilarious to change his own name to "Hingle McKringleberry" and facebook made him keep it that way for 30 days minimum before it could be changed back, lol! kids!